# include <iostream.h>
 # include    <conio.h>

 class Linked_list_Stack
    {
       private:
      struct node
         {
        int data;

        node *next;
         };

      node *top;
      node *entry;
      node *print;
      node *bottom;
      node *last_entry;
      node *second_last_entry;

       public:
      Linked_list_Stack( );

      void pop( );
      void push( );
      void print_list( );
      void show_working( );
    };


 /**************************************************************************///----------------------  Linked_list_Stack( )  --------------------------///**************************************************************************/

 Linked_list_Stack::Linked_list_Stack ( )
    {
       top=NULL;
       bottom=NULL;
    }

 /**************************************************************************///-------------------------------  push( )  ------------------------------///**************************************************************************/void Linked_list_Stack::push( )
    {
       int num;

       cout<<"\n\n\n\n\n\t Enter value to push onto Stack : ";
       cin>>num;

       entry=new node;

       if(bottom==NULL)
      {
         entry->data=num;
         entry->next=NULL;
         bottom=entry;
         top=entry;
      }

       else
      {
         entry->data=num;
         entry->next=NULL;
         top->next=entry;
         top=entry;
      }

       cout<<"\n\n\t *** "<<num<<" is pushed onto the Stack."<<endl;
       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }

 /**************************************************************************///----------------------------  pop( )  ----------------------------------///**************************************************************************/void Linked_list_Stack::pop( )
    {
       if(bottom==NULL)
      cout<<"\n\n\n\t ***  Error : Stack is empty. \n"<<endl;

       else
      {
         for(last_entry=bottom;last_entry->next!=NULL;
                         last_entry=last_entry->next)
        second_last_entry=last_entry;

         if(top==bottom)
        bottom=NULL;

         int poped_element=top->data;

         delete top;

         top=second_last_entry;
         top->next=NULL;

         cout<<"\n\n\n\t *** "<<poped_element<<" is poped from the Stack."<<endl;
      }

       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }

 /**************************************************************************///------------------------------  print_list( )  -------------------------///**************************************************************************/void Linked_list_Stack::print_list( )
    {
       print=bottom;

       if(print!=NULL)
      cout<<"\n\n\n\n\n\t Values pushed onto Stack are : \n"<<endl;

       else
      cout<<"\n\n\n\n\n\t *** Nothing to show. "<<endl;

       while(print!=NULL)
      {
         cout<<"\t "<<print->data<<endl;

         print=print->next;
      }

       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }

 /**************************************************************************///---------------------------  show_working( )  --------------------------///**************************************************************************/void Linked_list_Stack::show_working( )
    {
       char Key=NULL;

       do
      {
         clrscr( );

         gotoxy(5,5);
         cout<<"**********   Implementation of Linked List as a Stack   **********"<<endl;

         gotoxy(10,8);
         cout<<"Select one of the listed operation :"<<endl;

         gotoxy(15,10);
         cout<<"- Press \'P\' to Push a value"<<endl;

         gotoxy(15,12);
         cout<<"- Press \'O\' to Pop a value"<<endl;

         gotoxy(15,14);
         cout<<"- Press \'S\' to Print the values"<<endl;

         gotoxy(15,16);
         cout<<"- Press \'E\' to Exit"<<endl;

         Input:

         gotoxy(10,20);
         cout<<"                      ";

         gotoxy(10,20);
         cout<<"Enter your Choice : ";

         Key=getche( );

         if(int(Key)==27 || Key=='e' || Key=='E')
        break;

         elseif(Key=='p' || Key=='P')
        push( );

         elseif(Key=='o' || Key=='O')
        pop( );

         elseif(Key=='s' || Key=='S')
        print_list( );

         elsegoto Input;
      }
       while(1);
    }


 int main( )
    {
       Linked_list_Stack  obj;

       obj.show_working( );

       return 0;
    }